Lubricating oil and lubrication therewith



Patented Dec. 6, 1938 um'rso 'srarss PATENT orrics Arthur Walther Lewis,Elizabeth, N. .L, assignoi' to Tide Water Associated Oil Company,

yonne, N. 3., a corporation of Delaware 1 No Drawing. Application April2, 1937,

Serial No. 134,517

6 Claims.

This invention relates to lubricants intended for service in thelubrication of internal combustion engines. The invention moreparticularly is concerned with lubricating or motor oils of mineralhydrocarbon origin which are normally corrosive toward bearing metalalloys of the character of cadmium-silver, cadmium-nickel orcopper-lead, as well as those bearing metals of exceptionally high leadcontent (of the order of 75% to 99%) wherein minor proportions ofalloying metals impart unusual hardness to the alloy; and has, for animportant objective, the inhibition or prevention of deterioration ofsuch bearing metal in service by the corrosive action of the lubricantthereon.

Engine bearings comprising or surfaced with cadmium-silver, high-lead orlike alloys now are frequently employed in lieu of the more usualBabbitt metalbearings, in order to cope with extreme service conditionsof friction and temperature. These conditions are the consequences ofmodern developments in internal combustion engines making available highsustained speeds and requiring bearings formed of metals or alloyshaving greater resistance to wear, and further characterized by highermelting points necessary to prolonged life under the extreme thermalconditions existing during operation of the engine. Temperatures at thebearing surfaces during operation are, or may be, much higher in thecase of engines requiring these new bearings than formerly was thecircumstance with engines in which Babbitt metal bearings gavesatisfactory service. Experience with bearings of the character or typeexemplfied by cadmium-silver, cadmiumnickel, copper-lead and high-leadalloys has demonstrated, however, that their utility is greatly impairedby an extreme susceptibility to rapid deterioration by the corrosiveaction or effect of 50 lective solvents, exhibit a marked tendency to-,

ward corrosion of the bearings in question, although by other tokens thelubricant is of superior quality. Oxidation stability, as indicated bysludge or acid formation in conventional tests 1 indicative of thetendency toward deterioration many available lubricating oils.Particularly has of the oil itself in service, does not appear to havereliable correlation with the tendency of the oil to corrode bearingsurfaces. It is possible that the high bearing surface temperaturesexisting under service conditions with the new bearings may be a factorin occasioning the observed deleterious effect of motor oils thereupon.It would appear, also, that the problem of bearing corrosion, with whichthe present invention is particularly concerned, contrasts with problemsof lubricant deterioration per se', since oils characterized by longlife and good stability in conventional tests may, and frequently do,prove to be the most corrosive in bearing corrosion tests. No theory inexplanation of the observed corrosive action or the prevention thereof,as herein proposed according to the invention, is intended to be reliedupon.

According to the present invention, it has now been found that thecorrosive effect of lubricating 2o oils upon bearing surfaces of thecharacter referred to above maybe avoided in novel and effective mannerby incorporating with such oils particular compounds having a retardingor inhibiting effect in respect of such corrosion. More spe- 25cifically, the invention arises from the discovery that a compoundcomprising methylene amino aceto nitrile effects a very beneficialretardation of the corrosive action of internal combustion enginelubricating oils upon cadmium-silver, cad- 30 mium-nickel, copper-lead,high-lead and like bearing metal alloys. I

It is, therefore, an important object of the present invention toinhibit or retard the corrosive deterioration of these and like bearingmetal alloys in automotive service by providing a lubricant thereforcomprising a refined mineral hydrocarbon oil having incorporatedtherewith methylene amino aceto nitrile in small but effectiveproportion. Likewise, it is an object of the invention 0- to improve,and to prepare improved, motor oils of petroleum origin by incorporatingtherein I methylene amino aceto nitrile in corrosion inhibitingproportions. The provision of an inhibitor effective for such purposeand comprising a comw pound as aforementioned naturally is a majorobjective. I

Viewed in another aspect, the invention may be. regarded as encompassinga novel method of inbricating bearing metal surfaces, of the characterof cadmium-silver, cadmium'-nickel, copper-lead, high-lead or likealloys, by applying thereto a film of lubricant comprising mineralhydrocarbon oil having incorporated therewith a small but effectiveproportion of methylene amino aceto nitrile. With this method oflubrication it has been found that prolonged life and consequentimproved service may be attained in the use of these alloys as bearingmetals of internal combustion engines, particularly when operatingconditions such as high sustained speeds under load occasion unusuallyhigh bearing surfacetemperatures. Ordinarily, the oil selected for use,in applying the lubricating method of the invention to its intendedservice, will be of a character generally regarded as of superior gradeand refining. Thus, the invention finds particular utility in makingpossible the beneficial use of such oils by avoiding deleteriousconsequences otherwise encountered when no preventive measures are takenagainst the corrosive deterioration of bearing metal alloys ashereinbefore referred to. It will be understood, however, that theinvention contemplates no limitation in this respect, and that themethod of lubrication herein described may be practiced in conjunctionwith mineral hydrocarbon lubricating oils taken as a broad class andregardless of origin.

Methylene amino aceto nitrile is a compound which is believed to conformto the structural formula H: HzC=N-CCEN Solubility in mineralhydrocarbon oil ,of motor lubricating oil character is limited, but theproportion necessary to accomplish the objects of the present inventionis well within the limits of solubility. It sufiices, therefore, simplyto dissolve methylene amino aceto nitrile (if desired with moderateapplication of heat to facilitate solution) in motor oil intended forservice in internal combustion engines in order to prepare for thelubrication thereof according to the invention. Proportions as low as0.2% by weight of the compound dissolved in motor oil are shown by theillustrative data hereinafter presented to be markedly inhibitive of thecorrosion normally attending the use of many lubricating oils withbearing metals of the type comprising alloys as liereinbefore mentioned.The stated percentage is not intended as a limitation upon thecontemplated scope and practice of the invention, as obviously theinhibitor may be, and is intended to be, employed in any corrosioninhibiting proportion.

The tendency of motor oils to corrode bearings of the character inquestion may be determined by a convenient test which affords a readymethod of obtaining a comparative evaluation of motor oils in thelaboratory. In this test method a group of bearings, ordinarilyincluding at least one each of several of the newer bearing metal alloys(viz: cadmium-silver, cadmium-nickel and copper-lead) is supported in achamber in which air may circulate and the bearing surfaces are exposedfor a period of 22 hours to a stream of oil sprayed under pressurecontinuously upon the corrodible area. The oil is maintained at atemperature of approximately 335 F. and the spray is so directed as todisperse the oil over the surfaces of the bearings. Means are providedfor recirculating the sprayed oil so that a given quan tity is used fora given test, thus simulating service conditions in an engine. Themeasure of corrosion is taken as the loss in weight of the bearing perunit of exposed corrodible surface.

The test method described above is carried out in the familiar Underwoodcorrosion apparatus areaosa supplied by the Scientific InstrumentCompany of Detroit, Michigan, in accordance with General Motorsspecifications.

Results obtained utilizing the foregoing test for comparative evaluationof motor oils with and without an inhibitor according to the inventionprovide specific illustration of the value and inhibiting efiectivenessof methylene amino aceto nitrile. The oil used for the test was an S. A.E. 20 motor oil comprising a blend of well refined parafiinic basestocks and having an A. P. I. gravity of 30.1, Saybolt viscosity F. ofabout 300 seconds, Saybolt viscosity 210 F. of 54 seconds and flashpoint of 425 F. Inhibitor, when added, was used in an amount of 0.2% byweight based on the oil. During each run cadmium-silver, cadmium-nickeland copper-lead bearings all were present; and comparative losses inweight per square decimeter due to corrosion were observed as followsfor the respective bear ings:

While the utility of the invention has been illustrated specificallywith reference to a particular motor 011, no limitation is to beinferred therefrom, and other oils, whether or not comparable inspecification or origin, may be used in the lubrication of bearings ofthe type described in accordance with the invention.

I claim:

1. The method of lubricating bearings having substantially the corrosionsusceptibility characterizing cadmium-silver, cadmium-nickel andcopper-lead alloys, which consists in applying to the bearing surfaceslubricant comprising mineral hydrocarbon oil of a character normallytend ing to corrode said bearings and having incorporated thereincorrosion inhibiting proportions of methylene amino aceto nitrile.

2. The method of lubricating bearing surfaces in internal combustionengines, which bearing surfaces comprise an alloy having substantiallythe corrosion susceptibility characterizing cadmium-silver,cadmium-nickel and. copper-lead alloys, which consists in applying tosaid bearing surfaces lubricant comprising mineral hydrocarbon oil of acharacter normally tending to corrode said bearing surfaces and havingincorporated therein corrosion inhibiting proportions of methylene aminoaceto nitrile.

3. In the lubrication of bearing surfaces, at least one of which isformed of an alloy having substantially the corrosion susceptibilitycharacterizing cadmium-silver, cadmium-nickel and copper-lead alloys,with mineral hydrocarbon oil normally tending to cause substantial andrapid corrosion thereof, the method of inhibiting such corrosion, whichcomprises incorporating with said oil corrosion inhibiting proportionsof methylene amino aceto nitrile.

4. A lubricant for the lubrication of internal combustion enginesoperating at high sustained speeds and employing bearings presentingbearing surfaces of an alloy selected from the class of cadmium-silver,cadmium-nickel and copperlead alloys, which comprises a well refinedmineral lubricating oil of the character normally effective to causesubstantial corrosion of such bearingsurfaces, and added methylene amino'aceto nitrile in corrosion inhibiting proportions.

5. Mineral oil composition, comprising a hydrocarbon lubricating oil ofmotor oil character normally tending to corrode the type of bearingmetal having substantially the corrosion susceptibility characterizingcadmium-silver, cadmium nickel and copper-lead alloys when continuouslyapplied to the surface thereof for an extended period of time at an oiltemperature of 300 .F. or above,

and methylene amino aceto'nltrile in corrosion inhibiting proportions.

6. Mineral oil compositions, comprising a hydrocarbon lubricating oil ofa character normally tending to corrode the type of bearing metal having substantially the corrosion susceptibility characterizingcadmium-silver, cadmium-nickel and copper-lead alloys when continuouslyapplied to the surface thereof under service conditions,

and methylene amino aceto. nitrile incorporated 10 with said oil incorrosion inhilitlng proportions. ARTHUR WALTHER LEWIS.

